1. Field of the Invention
The present invention relates to a signature-conveying apparatus of a folding machine of a rotary press.
2. Description of Related Art
Conventional commercial rotary presses, such as the one shown in FIGS. 11 and 12, includes a folding machine which has a chopper-folding unit.
A folding machine of a type having the above mentioned chopper-folding unit causes continuous paper W printed in a printing portion of a rotary press to be introduced into a parallel folding portion 1 which incorporates a serration cylinder 2, a folding cylinder 3 and a gripping cylinder 4. The continuous paper W is cut into sheets each having a predetermined size at a position between the serration cylinder 2 and the folding cylinder 3. Then, the sheet is, between the folding cylinder 3 and the gripping cylinder 4, folded in parallel with the cutting line so that the size of the sheet is halved. Thus, signatures S1 are formed.
As shown in FIG. 11, the signatures S1 are held between an upper conveying belt 7a and a lower conveying belt 7b arranged to move at the same peripheral speed of each cylinder disposed in the parallel folding portion 1. Thus, the signatures S1 are conveyed toward a chopper-folding unit 9. The signature S1 moved by the upper and lower conveying belts 7a and 7b is brought into contact with a stopper 15 of the chopper-folding unit 9 so as to be stopped. In synchronization with the stoppage timing, a chopper blade is pressed against the central portion of the signature S1 so that a signature S2 folded half in a direction perpendicular to the cutting line of the signature S1 is formed.
A folding machine structured as shown in FIG. 12 is employed by a rotary press of a type which usually processes printed matter which is chopper-folded. As shown in FIG. 12, the foregoing folding machine incorporates a speed-reduction cylinder 5 disposed between a parallel folding portion 1 and chopper-folding units 9A and 9B and arranged to be rotated at a peripheral speed lower than that of each cylinder disposed in the parallel folding portion 1. Moreover, the folding machine shown in FIG. 12 incorporates a delivery cylinder 6 which is in contact with the speed-reduction cylinder 5 and arranged to be rotated at the same peripheral speed as that of the speed-reduction cylinder.
The cylinders 5 and 6 are connected to corresponding chopper-folding units 9A and 9B which are two units disposed vertically. The signature S1 discharged from the gripping cylinder 4 is delivered from the gripping cylinder 4 to the speed-reduction cylinder 5 along the surfaces of the two cylinders 4 and 5. The signatures S1 are alternately delivered to a passage formed from the speed-reduction cylinder 5 to the lower chopper-folding unit 9A and another passage formed from the speed-reduction cylinder 5 to the upper chopper-folding unit 9B through the delivery cylinder 6.
The signature S1 allowed to pass through the lower conveying belts 7a and 7b and the delivery cylinder 6 and alternately placed on the upper conveying belts 8a and 8b are held between the conveying belts 7a and 7b and the conveying belts 8a and 8b so as to be conveyed. Then, the is leading end of the signature S1 is brought into contact with each stopper 15 of the chopper-folding units 9A and 9B. At this time, the chopper blade is pressed against the central portion of the signature S1 so that a signature S2 folded into two perpendicular to the cutting line of the signature S1 is formed.
In the folding machine incorporating the speed-reduction cylinder 5, the two chopper-folding units 9A and 9B are alternately operated as described above. The speed, at which the signature S1 is conveyed to the chopper-folding units 9A and 9B, can be reduced. As a result, even if the printing speed of the rotary press is raised, repulsion, which is produced when the signature S1 is brought into contact with the stopper 15 of each of the chopper-folding units 9A and 9B, can be reduced. Therefore, the folding accuracy can be stabilized and, thus, the chopper-folding operation can be performed at high speed.